Radiotherapy in Older Women With Low-Risk Breast Cancer: Why Has Practice Not Changed?

Abstract

TO THEEDITOR: The editorial 1 regarding the publication by Soulos et al 2 stated that some older women with breast cancer are being clearly overtreated. Most clinicians will agree with this statement. However, the author also indicated that “offering radiation therapy to a woman with a good-prognosis tumor and a life expectancy of less than 5 years does not seem indicated.” 1(p1578) Although this statement represents a publicly shared standard, 3,4 it is not supported by facts. Several studies have evaluated the role of adjuvant radiotherapy, and all indicated a benefit of radiotherapy in reducing locoregional recurrence rates. 5-11 The Toronto Breast Cancer Study indicated that the relapse rate was 1.2% with tamoxifen alone and decreased to 0% when tamoxifen was given with whole-breast irradiation (WBI). There were no significant differences in the distant recurrence rates, questioning the role of tamoxifen alone in controlling systemic disease in this subgroup of patients. 7 The Cancer and Leukemia Group B 9343 trial published in the same issue of New England Journal of Medicine concurred with the results of the Toronto group. In this study, women age 70 years with tumors 2 cm were assigned to tamoxifen either with or without WBI. The locoregional control recurrence rates were lower in the combined WBI-tamoxifen group (1% v 4%; P .001). 6 These results were supported in a later update abstract presented in 2010, where the only significantly different outcome was local recurrence with a difference of 2% in the irradiated group and 9% in those women who did not receive adjuvant radiotherapy. 5 In view of these facts, it is not clear why omitting radiotherapy in older patients with low-risk disease has become a publicly shared standard. Maybe it is because there were no significant differences between the two groups with regard to the rates of mastectomy for local recurrence, distant metastases, or 5-year rates of overall survival. 3,5-7,12 Giordano 1 commented that older women with low-risk breast cancer treated with adjuvant radiotherapy are at risk for unnecessary adverse effects, inconvenience of treatment, and possibly increased personal costs for a treatment unlikely to offer them any benefit. This could also be applied to the endocrine treatment, as both classes of endocrine agents have their own recognized adverse effects and